Boat cradle for mobile trailers

ABSTRACT

A trailer supported cradle for boats which minimizes the force required to mobilize a boat with respect to its trailer during loading and unloading activities and which substantially increases the area of contact between the boar hull and its supporting cradle to reduce the stress on the hull of the boat due to acceleration forces developed during transportation of the boat upon the tractor-drawn trailer, said support including elongated endless belts trained about articulately mounted sets of coplanar pulleys.

United States Patent 1 Johnson [54] BOAT CRADLE FOR MOBILE TRAILERS [76]Inventor: Lawrence N. Johnson, Route No. 1,

Box 251A, Spokane, Wash.

[22] Filed: July 29, 1971 [21] Appl. No.: 167,186

[52] U.S. Cl. ..2l4/84, 193/35 R [51] Int. Cl. ..B60p l/52, 860p 3/10[58] Field of Search 214/84; 280/414;

193/35 R, 35 C, 38; 198/192 A, 193

[56] References Cited UNITED STATES PATENTS 2,410,611 11/1946 Pratt etal ..198/193 1 May 8, 1973 3/1967 Desfilles ..2l4/84 PrimaryExaminer-Albert J. Makay Attorney-Norman H. Huff [57] ABSTRACT A trailersupported cradle for boats which minimizes the force required tomobilize a boat with respect to its trailer during loading and unloadingactivities and which substantially increases the area of contact betweenthe boar hull and its supporting cradle to reduce the stress on the hullof the boat due to acceleration forces developed during transportationof the boat upon the tractor-drawn trailer, said support includingelongated endless belts trained about articulately mounted sets ofcoplanar pulleys.

4 Claims, 5 Drawing Figures Patented May 8, 1973 3,731,826

2 Sheets-Sheet 1 r a, a,

F l G. 2

INVENTOR LAWRENCE N. JOHNSON ATTORNEY Patented May 8, 1973 3,731,826

2 Sheets-Sheet 2 FIG.5

LAWRENCEBLJOHNSON ATWDRNEY BOAT CRADLE FOR MOBILE TRAILERS BACKGROUND OFTHE INVENTION My present invention relates to boat trailers and moreparticularly toimproved boat loading, supporting and unloading mechanismcarried by transporting trailers.

When a boat is in the water, its hull is not normally subjected tolocalized areas of stress. However, since boating has become morepopular, instead of one trip to a body of water at the beginning of theboating season and one return trip at the close thereof, it is nowcustomary to transport a boat to and from its point of use each time itis used. A boat is thus subjected to unusual stresses at localized areasmany times throughout the boating season. l-leretofore, trailers havebeen provided with supporting rollers for supporting and cradling a boathull during the loading and unloading operation and also during themovement of the boat from one location to another by means of a trailer.The rollers are normally constructed of at least a semirigid materialand through they may be articulately supported upon the trailer, as inmy prior U.S. Pat. No. 3,155 ,249, still they are normally fixedin-so-far as their contact with the hull of a loaded boat is concerned.The contact area between each roller and the outer surface of the hullof the boat comprises a thin line extending parallel to the axis ofrotation of the roller and a length equal to the width of the roller. Asthe size and weight of boats increases the custom has been to multiplythe number of rollers in an attempt to increase the supporting area andthereby minimize the localized hull stresses. However, as rollers aremultiplied, the frictional resistance to loading and unloading movementsincreases proportionately.

As an alternative method of supporting the boat on a trailer during thetrailing operation, pad assemblies having relatively large bearingsurfaces were considered. This method was highly desireable during thetrailing operations, inasmuch as the large load area of In view of theforegoing problems, there were at tempts to provide a boat trailer whichwould support a boat during the trailing operations by means of padassemblies having large bearing areas and by means of roller assembliesduring the loading and unloading operations. While trailers of this typehave been provided with some success, they have been complicated andhave required considerable time and effort on the part of the boatowner, and, therefore have'not been widely accepted. Most of the priorart assemblies which are provided with roller assemblies for loading andunloading the boat as well as pad assemblies for supporting a boatduring a trailing operation have a tiltable frame section with rollersupport means thereon.

ln U.S. Pat. No. 3,082,892, one such boat trailer having a tiltableframe section with roller support as well as pad assemblies isdisclosed. When a tiltable section is tilted to the loading andunloading positions, the roller supports are elevated above the padassemblies. Not only is it necessary to tilt the tiltable frame sectionin order to transfer the load of the boat from the pad assembly to theroller support means and vice versa, but the hull is still subjectedto'the stress of being transferred to and from and moved over rollers.Thus the patent does not overcome the problem of relieving stress on thehull of the boat.

A trailer having a complicated, telescoping frame with a tiltablesection is disclosed in U.S. Pat. No. 3,140,003. While the structurepurports to reduce the manual labor, it does not solve the problems ofstress and friction on the boat hull. Still another prior art trailerhaving a tiltable section is provided in U.S. Pat. No. 3,097,755. Onceagain, the hull of the boat is subjected to stresses and possible damagefrom the rollers. The above described trailers generally employ aconventional system of stationary rollers. The boat rides across therollers during the loading and unloading and, consequently is subjectedto a great deal of friction, stresses, bumping and the like.

SUMMARY OF THE INVENTION The present invention includes elongated beltswhich are supported upon series of coplanar pulleys and thus provide thevery substantial benefit of increased hull support area found in the padassemblies of the prior art and yet obviate the necessity for increasedrollers thus preventing any substantial increase in the forces requiredto move the boat with respect to the trailer.

Moreover, during the trailing operation, in addition to the load factorshereinbefore mentioned, there is an abrading function which takes placebetween the rollers and the boat hull with such severity, in some cases,as to wear through the varnish and gel coat. The dust and dirt stirredup by the movement of the vehicle and air results in abrasive granulesbeing deposited upon the rollers and the continuous movements fromtrailing over the road results in its migration between the rollers andhull causing the spot wear. Over a period of time holes will develop atthe support points.

The rapidity with which the movement and abrasive will wear the hull is,of course, varied by the P.S.l. sup,- ported at the rollers. My presentinvention reduces the forces involved from between 50 and P.S.l.downwardly to from 3 to 5 P.S.l. preferably and thus materially reducesthe abrading action during trailing operations.

Accordingly, it is an object of the present invention to provide animproved boat mobilizing and support mechanism for trailers.

Yet another object of the present invention lies in the provision of animproved boat mobilizing and support mechanism which distributes theload over an increased area of the hull and particularly does notlocalize any stress at the keel.

A further object of the present invention is to provide a unique endlessbelt admirably adapted to facilitate mobilization of the boat duringloading and unloading operations, yet which provides ample hull supportduring transportation of the boat overland from place to place.

The foregoing and other objects and advantages of the present inventionwill become more apparent and meaningful during the course of thefollowing specification when considered in association with theaccompanying draings wherein a preferred form of the invention isgraphically illustrated. It is to be understood however, that thedrawings are illustrative only and are not intended to limit the scopeof the invention. It should also be understood that various changes inconstruction may be resorted to in the course of manufacture without inany way departing from the spirit of the invention which is to beunderstood only in accordance with the appended claims. Furthermore, itis to be understood that while the invention is described in oneparticular association, it is not my intention to unnecessarily limitthe applicability of the invention, but I desire to reverse to myselfthe claimed invention for every use of which it is now known orsubsequently discovered to be susceptible.

Other advantages and features of this invention will become apparentfrom the more detailed description following in which like referencenumerals are employed to designate similar parts in the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of a boat trailer embodying the supportmechanism constituting the subjects matter of this work;

FIG. 2 is an enlarged elevation of one supporting belt assembly;

FIG. 3 is a lateral section as at line 3-3 of FIG. 2;

FIG. 4 is a lateral section as at line 4-4 of FIG. 2 upon a furtherenlarged scale; and

FIG. 5 is a fragmentary perspective of a section of the novel belt.

DESCRIPTION OF PREFERRED EMBODIMENT Referring now more particularly tothe drawings, one embodiment of a boat trailer in accord with thepresent invention is shown generally at 10. The trailer includes a rigidframe, shown generally at 11, and having a longitudinally extendingdraft tongue 12 and mobilizing wheels 13, one journaled to support eachside of the frame 11 in conventional manner. The forward end of thedraft tongue may be provided with any suitable releasable coullingelement as, for example, a conventional ball hitch socket (not shown)for engagement with a complementary element (not shown) adapted to becarried by a drawing vehicle or tractor.

Boat cradle means, shown generally by the numeral 14, are carried by therigid frame 11 and constitute means for mobilizing a boat during loadingand unloading movements and sequentially supporting the boat fortransportation over land upon the'trailer.

The boat cradle means 14 comprises plural, strategically disposed boatmobilizing and support means 15- -15 of a predetermined selectivequantity to provide plural supporting areas for the boat hull at pointsspaced from the boats keel (not shown) or the plateroll median of thetrailer frame 11.

Each support means includes an endless belt 16 having a boat supportflight 16a presented so that its outer face 16b will contact the hullsurface (not shown) of a boat. The belt 16 includes a truncated cuneatebead l7 midway the cross-flange 18 and on its inner face, opposed to theouter face 16b. Molded in the rubber-like body forming the bead 17 andflange 18 are spaced reinforcing leaves 19-19 united by non-extensilecables 20-20, which cables preclude unwanted stretching of the belt. Theleaves 19-19 provide lateral edge wupport to the belt face 16b tomaximize the load distribution of the hull face upon the support flightface 16b. The said face 16b is laterally concave and thus the flight 16ahas an elongate cylindroidal face which will yield to conform to thecontour of a boat hull when sufficient gravitationally induced force isapplied by the hull surface to the face 16b.

To facilitate mobilization of a boat onto and off from the cradle 14,the belts 15 are each trained to traverse a path dictated by coplanarpulleys 21 and 22 journaled on spindles 23-23 fixed to extendperpendicularly from the mounting bar 24 rockably carried by a finger 25welded or otherwise secured in near spaced relation to a rock arm 26fixed perpendicularly at the end of a frame mounted rock shaft 27. Therock shafts 27 are mounted for rocking movements on axes substantiallyparallel to the longitudinal axis of the trailer, whereby the rock arms26 tilt in substantially vertical planes athwart of the axis of saidtrailer and the mounting bars pivot about the axes of the fingers 25;all said movements being within predetermined limits.

The pulleys 21 and 22 are provided with annular grooves companion to thebeads 17 and thus provide means for precluding accidental displacementof the belts 15 from their paths.

The groove defining flanges 28-28 of the pulleys 21 and 22 are axiallyincreased to provide annular support faces upon which the inner faces ofthe belt 16 are supported.

It is thus seen that I have provided plural spaced articulatelysupported boat mobilizing and support means which provides greatlyincreased hull support area over a similar'wuantity of rollers and yetone which provides very little, if, any more resistance to movements ofa boat during loading and unloading manuevers.

Having thus described my invention, I desire to secure myv LettersPatent of the United States the following:

1. In aboat trailer including a wheel-supported frame having alongitudinally extending draft tongue adapted to be releasably coupledto a tractor, means useable in loading, supporting and unloading a boat,said means comprising:

a boat cradle comprised of plural spaced boat mobilizing and supportmeans supported at predetermined positions upon said frame and removedfrom a position corresponding to the keel of a boat;

at least selected ones of said boat mobilizing and support means eachhaving plural co-planar pulleys journaled on substantially parallel axesdisposed substantially athwart of the longitudinal axis of said trailer;

an endless belt trained about said pulleys to traverse an obround pathperipherally of said pulleys and adapted to present a boat supportflight to the hull of a boat supported upon said trailer;

said belt having a cylindroidal concave, axially coplanar outer face onsaid boat support flight and progressively more susceptible of pressuredeformation from its center toward its opposed edges; and

means for precluding accidental displacement of said belt from its saidpath.

2. The combination ofclaim 1 wherein additionally,

the said boat mobilizing and support means are articulately supportedupon said frame for limited angulation to substantially conform to thehull contour variations of a boat being moved longitudinally upon saidtrailer.

3. The combination of claim 2 wherein additionally pairs of said boatmobilizing and support means are pivotally mounted one at each end of abar mounted to 5 tiltingmovements in a vertical plane athwart of atrailer, there being means restricting all movements

1. In a boat trailer including a wheel-supported frame having alongitudinally extending draft tongue adapted to be releasably coupledto a tractor, means useable in loading, supporting and unloading a boat,said means comprising: a boat cradle comprised of plural spaced boatmobilizing and support means supported at predetermined positions uponsaid frame and removed from a position corresponding to the keel of aboat; at least selected ones of said boat mobilizing and support meanseach having plural co-planar pulleys journaled on substantially parallelaxes disposed substantially athwart of the longitudinal axis of saidtrailer; an endless belt trained about said pulleys to traverse anobround path peripherally of said pulleys and adapted to present a boatsupport flight to the hull of a boat supported upon said trailer; saidbelt having a cylindroidal concave, axially co-planar outer face on saidboat support flight and progressively more susceptible of pressuredeformation from its center toward its opposed edges; and means forprecluding accidental displacement of said belt from its said path. 2.The combination of claim 1 wherein additionally, the said boatmobilizing and support means are articulately supported upon said framefor limited angulation to substantially conform to the hull contourvariations of a boat being moved longitudinally upon said trailer. 3.The combination of claim 2 wherein additionally pairs of said boatmobilizing and support means are pivotally mounted one at each end of abar mounted to tilting movements in a vertical plane athwart of atrailer, there being means restricting all movements withinpredetermined limits.
 4. The combination of claim 3 wherein additionallyfore and aft pairs of said boat mobilizing and support means are unitedfor coincidental tilting movements in vertical planes athwart of thetrailer.